A swivel joint comprises an outer ring having a cavity in the form of a portion of sphere, and an inner ring whose form is partly spherical and which is housed in the spherical cavity of the outer ring.
Various solutions have been proposed for assembling the inner ring in the cavity of the outer ring. In certain swivel joints, the outer ring is split, this enabling it to be opened elastically and making it possible to introduce the inner ring therein. In other swivel joints, the outer ring is pressed on the inner ring. It is also possible to constitute the swivel joint with the aid of several pieces added together, assembled by a band or by wilding.
Swivel joints are also known in which the cavity of the outer ring presents two diametrically opposite notches in part of its thickness, the diameter of these notches being equal to the diameter of the inner ring and their width being equal to that of this ring. It is possible to place the inner ring in position by orienting it through 90.degree. with respect to its normal position; it then suffices to pivot the inner ring to return it to its correct orientation.
However, these swivel joints present drawbacks which limit their domains of application; in particular, they can hardly be used when the swivel joint is subjected to a high radial load or to an axial load. In the case of a swivel joint with conventional notches, for example, these notches considerably reduce the surface of contact of the two rings and the resulting concentration of the efforts on the remaining surface brings about rapid deterioration of the swivel joint.
U.S. Pat. No. 3,007,747 relates to a swivel joint whose inner ring comprises a series of relatively narrow notches defining radial annular ribs, whilst its outer ring presents a series of notches allowing passage of the annular ribs of the inner ring. However, this swivel joint is even less resistant to an axial load, particularly due to the thinness of the ribs which may bend under the effect of this load.